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Update of  Analysis ~LEPS Collaboration Meeting in Taiwan

Update of  Analysis ~LEPS Collaboration Meeting in Taiwan. Nuclear Physics Group, Academia Sinica Bo-Ru, Lin 2006/01/12. Outline. Φ photoproduction using LD2 target Validity of momentum calculation Determination of E γ smearing Determination of Appropriate mass offshell effect

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Update of  Analysis ~LEPS Collaboration Meeting in Taiwan

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  1. Update of Analysis~LEPS Collaboration Meeting in Taiwan Nuclear Physics Group, Academia Sinica Bo-Ru, Lin 2006/01/12

  2. Outline • Φphotoproduction using LD2 target • Validity of momentum calculation • Determination of Eγ smearing • Determination of Appropriate mass offshell effect • t-resolution • dN/dt fitting • Background estimation

  3. p, n, or D ? Φ-photoproduction using LD2 target. • Incoherent Interaction：Photon interact with constituent nucleon, which is proton or neutron. • Coherent Interaction：Photon interact with deuteron as a whole.

  4. Pseudo-scalar Exchange Isospin effect in Coherent production : isoscalar η:isoscalar Allowed Forbidden π: isovector D : isoscalar Conjecture： By isospin conservation we should be able to separate πfrom the wholeexchanging channels.

  5. MMd of LD2, and LH2 Missing mass distributions provide us a tool. LD2 LH2

  6. Validity of momentum Calculation Accredited Md = 1.875 GeV Accredited MΛ = 1.520 GeV

  7. Validity of momentum Calculation Accredited Mp = 0.938 GeV

  8. Validity of momentum Calculation Accredited MΦ = 0.938 GeV

  9. Determination of appropriate MC Eγ smearing MMp fitting of LH2 real data using different Eγ smearing 15 Mev Smearing

  10. Determination of appropriate Eγ smearing Two component (11.64 MeV) Smearing 10 Mev Smearing

  11. Determination of Appropriate mass offshell effect Do subtraction and fit with gaussian distribution. Compare the result with coherent distribution Use MC Incoherent MMd fit LD2 MMd (in the region 1.9~2.1)

  12. Determination of Appropriate mass offshell effect

  13. Determination of Appropriate mass offshell effect

  14. Determination of Appropriate mass offshell effect

  15. t - resolution ~ sigma plot t-in : from event generator t-out : deduced in the way the same as real data Fit (t-in) – (t-out) with gaussian distribution to get σ value The t-resolution is better than 0.02 GeV

  16. MMd Fitting to Separate Coherent from Incoherent events Fitting of MMd of LD2 real data using Mote-Carlo generated incoherent, coherent events. coherent incoherent sum

  17. MMd MMp Cross check of MMd, and MMp Fitting

  18. Coherent LD2 dN/dt Fitting Fitting Formula： intercept slope

  19. t bin : 20 MeV t bin : 30 MeV t bin : 40 MeV Coherent LD2 dN/dt Fitting

  20. t bin : 20 MeV t bin : 30 MeV t bin : 40 MeV Coherent LD2 Common slope dN/dt Fitting Slope : 20~23 Slope with last Eγbin removed : 17 ~19

  21. Incoherent LD2 dN/dt Fitting

  22. Incoherent LD2 Common slope dN/dt Fitting

  23. Incoherent LH2 Coherent dN/dt Fitting of coherent, incoherent, LH2 results Coherent Slope : ~18.5 Incoherent Slope : ~4.0 LH2 Slope : ~3.6

  24. Background Estimation 10 Mev cut

  25. MC Backgrounds Invm-kk MMd MMp None-resonant KKn Λ(1520) None-resonant KKd

  26. Multidimensional Fitting LD2 Data Coherent Invm-KK MMd MMp Incoherent Sum of all Fit invm-KK, MMd, MMp simultaneously without background.

  27. LD2 Data Coherent Incoherent Sum of BG Sum of all Sum of BG KKn Λ(1520) Multidimensional Fitting Invm-KK MMd MMp KKd

  28. LD2 Data Coherent Incoherent Sum of BG Sum of all Multidimensional Fitting Invm-KK MMd MMp Next step : Apply the same procedure with t-binning

  29. Brief Summary • Stable results of preliminary dN/dt analysis are acquired. • Background estimation in every t, Eγ bin to acquire pure Φ events. Thank you for paying attention

  30. Backup Slides

  31. MMd MMd, using smaller binning

  32. Determination of Appropriate mass offshell effect ~ Results of other Ntuples

  33. Determination of Appropriate mass offshell effect ~ Results of other Ntuples

  34. Determination of Appropriate mass offshell effect ~ Results of other Ntuples

  35. Determination of Appropriate mass offshell effect ~ Results of other Ntuples

  36. Determination of Appropriate mass offshell effect ~ Results of other Ntuples

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